The Telemark multimode filter module is based on the filter of the legendary Telemark semi-modular synthesizer.
It’s routes lie in the original 1970s Oberheim SEM, though it has developed a character of its own.
The filter is a 12db/Octave multimode type. Multimode means there are more than one type of filter output.
There are in fact four: low pass, band pass, high pass and notch filter. Additionally, notch filter can be varied for an even wider range of sounds.

Use of Gain and Q allow for even wider possibilities.
No special knowledge is required to use this filter. Just plug your audio in the left, and your audio out on the right.
Optionally (and recommended!) patch a control voltage in to give the sound movement.